We have identified four principal science themes for the Northern Light:

The search for life
There has been no definitive evidence of life’s existing on Mars to date. Early Viking experiments were inconsistent in their results, and the analyses of recent fossil evidence found in Mars meteorites cannot disprove the possibility of cross-contamination or of an explanation by a non-biological mechanism. We will conduct macroscopic and microscopic searches for evidence of life. Macroscopically, we will examine the atmosphere to look for biomarker gases and for compositional variations that would indicate active surface sources. Microscopically, we will conduct a spectroscopic examination of the surface and the immediate subsurface for signs of life. We also plan to conduct tests to identify the presence of biological chemical compounds, such as chlorophyll.

The search for water
There is mounting evidence that liquid water once flowed on the surface of Mars. Large-scale deposits of surface-water ice have been tentatively identified at the planet’s poles. There is geophysical evidence of surface features formed by alluvial action and of ancient shorelines and ocean basins. To date, however, there have been no direct surface measurements of water deposits. We will conduct a spectroscopic search for water on the surface and in the atmosphere. We will also perform 3D subsurface imaging by active-seismic search and ground-penetrating radar to examine fine-scale subsurface geology and to search for permafrost and evidence of sedimentary rock formations that would indicate a previous presence of surface water.

The investigation of the atmosphere and radiative balance
Our current understanding of the Martian atmosphere is limited by a lack of measurement data. We will make daily composition measurements of known atmospheric species with spectra between 250-2500 nm (including water, ozone, oxygen, carbon dioxide, methane and aerosol) and search for undetected species. We will also obtain meteorology data, information on how key atmospheric species are partitioned and altitude-profile-composition information. Our lander-based instrumentation will allow us to observe directly the atmospheric surface environment below the boundary layer, which is unlikely to be observed by remote spacecraft sensing. We shall also be able to measure directly the surface-radiation flux and separate direct and diffuse flux components. We will use this data to improve our current understanding of the Martian atmospheric environment, its chemistry and variation. We will look for atmospheric gases that would support the indirect evidence of recent volcanism, and indicate the presence of life. We will also be able to provide a ground-based validation point to compare results from orbiting atmospheric instruments and from other landers deployed during our mission.

The preparation for a sample return mission
Sample return is a long-term scientific objective of the international Mars-exploration effort., Our seismic and ground-penetrating-radar experiments will provide unique 3D images of the fine-scale subsurface structure in the first 10s of meters of the Martian surface. Our package will add an additional surface-reference site, providing invaluable new information on the geological composition of Mars. This precursor investigation will enable future mission planners to employ appropriate drilling technology to gather subsurface samples for return for analysis on Earth. It will also enable Canada to develop further our space technology and to take a leading role in these missions as they are conceived during the next decade.